1. Field of the Invention
This invention pertains to automatic weapons employing soft recoil and particularly to recoil force control for compensating for the in line gravitational component of the weapon gun barrel during recoil and counter-recoil.
2. Description of the Prior Art
In absorbing the impulse from firing in most large weapons, the recoiling parts are brought to rest by hydraulic pressure usually with the use of cylinders and pistons or rams which are coupled to the barrel and push fluid through an orifice directly as the gun barrel is moving.
It is known to use a parabolic type valve so that the changing orifice area is proportional to the square root of the remaining distance in recoil. The pressure required to push oil through an orifice is proportional to the velocity of the oil squared. Similarly, the energy necessary to bring the gun barrel to rest is proportional to the velocity of the gun barrel squared. These two characteristics are thus employed in the parabolic valve to bring the gun barrel to rest in recoil with a constant force.
A difficulty with the recoil arresting system is that it does not compensate for the component of the weight or gravity force of the gun barrel and attached moving structure in the direction of recoil. Thus, this weight component or potential energy will be added to or subtracted from the kinetic energy of the recoiling parts depending on whether the gun is elevated or depressed.
Almost all large weapons after recoiling from firing are designed to be propelled forward by pressurized air or oil generally using an air-oil accumulator known as a recuperator. In soft recoil weapons the round is fired as the barrel is moving forward and the recoil caused by the round brings the forward motion of the barrel to rest and then pushes it back to its rearward position. The impulse of the round since it is fired as the gun barrel is still moving forward in counter-recoil is absorbed partially by bringing the forward motion of the gun barrel to rest and the rest goes to produce recoil energy moving the gun barrel rearwardly. The recoil force can be reduced significantly using the soft recoil approach. When the gun barrel is elevated, however, the pressure stored in the recuperator may not be sufficient to give the barrel sufficient forward velocity at the time the round is fired so that the recoil from the round will cause the gun to recoil too severely, developing an excessive reaction force. In the alternative, if the gun is pointed downward, the pressure in the recuperator will send the gun barrel forward at such a velocity that the recoil force will not be sufficient to drive the barrel all the way back to its rearward position. This condition has heretofore precluded use of the soft recoil principle in automatic weapons that must recoil a fixed distance to facilitate loading from stationary magazines. Thus, there is a need for compensating for the component of gravity or weight of the gun barrel in the recoil and counter-recoil direction caused by the elevational position of the gun barrel.